Until recently, there has been general agreement that improvement and preservation of water quality, though costly, provided economic and social benefits that outweighed the expense. Now, however, some observers are beginning to question whether the costs of the 1972 Water Pollution Control Act may actually exceed those benefits. This book provides answers to some of the questions that have been raised. The authors give measures of several important nonmarket benefits of improved water quality in Colorado's South Platte River Basin and empirically test and confirm the Weisbrod and Krutilla proposals that the general public may be willing to pay for preservation of environmental amenities and that option value and other preservation values must be added to recreation-use values to give an accurate picture of the social benefits of environmental preservation and restoration. Their findings include the fact that even those who do not expect to use the river basin for recreation are willing to pay for the maintenance of a natural ecosystem and to bequest clean water to future generations. The authors also arrive at average amounts households are willing to pay for improved water quality to enhance enjoyment of water-based recreation activities. They suggest that, without such information, it is highly unlikely that sufficient resources will be allocated for the preservation of unique environments and for the improvement of those being degraded.